Common Factor Calculator – Find Shared Factors of Numbers
List every factor shared by two numbers.
About the Common Factor Calculator
What is the Common Factor Calculator?
A common factor calculator lists every whole number that divides both of two integers exactly.
Why use this calculator?
Seeing the shared factors makes it obvious how to reduce fractions or split quantities equally across two groups.
How to use it
- Enter two positive integers.
- Read the complete list of shared factors.
- The last item is the greatest common factor.
Formula
All divisors of the GCD of the two numbers.
Two numbers with no common factor above 1 are called coprime.
Frequently Asked Questions
Are 1 and the numbers themselves always common factors?
1 always divides both. Each number also divides itself, so both count as shared factors.
What is a common factor used for?
Reducing fractions to lowest terms and finding the biggest equal share for splitting.
What order of operations does this use?
It follows standard PEMDAS/BODMAS rules: parentheses, exponents, multiplication and division, then addition and subtraction.
How precise are the answers?
The calculator uses double-precision floating-point math (about 15 significant digits) and rounds the display. For exact symbolic results use dedicated algebra software.
Can I enter negative numbers or decimals?
Yes. Negative values, decimals and very large or small numbers are all supported unless a field says otherwise.
What does it mean if I get an error?
Errors usually mean an invalid input, such as division by zero or a negative value where only positives make sense. Check your entries and try again.
Is this calculator free to use?
Yes. Every calculator on this site is completely free, with no hidden fees, no subscriptions and no limits on how many times you can use it.
How accurate are the results?
We use standard, widely accepted formulas and calculate in your browser using double-precision arithmetic. Results are rounded for readability, so treat them as reliable estimates rather than a guarantee. Real-world factors can vary the true figure.
Can I add this calculator to my own website?
Yes. Open this calculator page and use the "Add to your website" box in the sidebar to copy a ready-made iframe snippet, then paste it into any HTML page.
Does it work on a phone or tablet?
Yes. The layout is fully responsive, so it works on desktops, laptops, tablets and mobile phones, and every input adapts to touch screens.